In recent years, due to the development of science and technology, the demand for rare earth becomes increasingly greater, and the dependence of fields such as high-intensity permanent magnets, electronic display fluorescence powder, renewable energy techniques and alloy industry on rare earth becomes increasingly stronger. How to guarantee the stable supply of rare earth has already become a great challenge to the current society.
Among more than 250 known rare earth ores, monazite is one of three major rare earth ores which are commercially mined, is also a second important phosphate rare earth ore in the world, and is mainly distributed in Australia, United States, Africa, Bayan Obo of China, etc. The content of rare earth oxide in monazite is about 70%. Different from bastnaesite, monazite further contains 4-12% of thorium and a small amount of uranium.
At present, commonly used rare earth ore enrichment methods mainly include gravity separation, magnetic separation, electrostatic separation and flotation. Monazite can exist in the form of seaside sand stone or vein-like ore. Gravity separation and magnetic separation can be utilized for enrichment aiming at monazite in the form of seaside sand stone. CN102614978 reports a gravity separation and magnetic separation combined method for respectively enriching ilmenite, monazite and zirconite from the seaside sand ore. A commonly used method for the vein-like ore is flotation. U.S. Pat. No. 2,610,738 reports a comparatively typical flotation method. WO1991016986 improves the flotation agent and the flotation method, such that the flotation effect of monazite is greatly improved. However, monazite can also be paragenetic with apatite, which mainly exists in Australia, United States and Russia. Apatite is mainly used for preparing fertilizer and can also be used for extracting some rare earth metals.
At present, there are few of researches aiming at monazite and apatite paragenetic ore enrichment methods. The traditional enrichment methods not only are poor in effect and complex in process, but also easily cause environmental pollution. Therefore, it becomes a problem which needs to be urgently solved to find an effective method for respectively enriching monazite and apatite from monazite and apatite paragenetic ores.